mingw: use strftime() directly in UCRT builds by dscho · Pull Request #6130 · git-for-windows/git

dscho · 2026-03-17T07:38:50Z

Currently, Git for Windows is built off of the MINGW64 tool chain. But this will have to change because the MSYS2 project deprecated this tool chain in favor of UCRT64. Of course, that's only possible because they dropped support for Windows 8.1, which Git for Windows will probably have to do relatively soon. The best time to do that is probably the Git 3.0 inflection point when we already promised to drop support for older Windows versions.

To prepare for such a huge change, I investigated what needs to be changed in Git for Windows' source code. And the good news is there's actually not very much. This here patch seems to be the only change that's necessary, and not even strictly necessary: the mingw_strftime() wrapper would still do the right thing. It would just uselessly load the same function that's already loaded, dynamically, again.

The strerror() override is guarded by an #ifndef _UCRT,
PRIuMAX resolves to standard "llu" via <inttypes.h> (note that __MINGW64_VERSION_MAJOR is defined both in MINGW64 and UCRT64, by virtue of using the mingw-w64-headers),
__USE_MINGW_ANSI_STDIO=0 is irrelevant because _UCRT short-circuits it, and
SNPRINTF_RETURNS_BOGUS hasn't been set for Git for Windows' builds since ec47a33, i.e. for a really long time.

rimrul · 2026-03-17T08:32:31Z

I think this might regress #863 on UCRT.

compat/mingw.c

The `mingw_strftime()` wrapper exists to work around msvcrt.dll's incomplete `strftime()` implementation by dynamically loading the version from ucrtbase.dll at runtime via `LoadLibrary()` + `GetProcAddress()`. When the binary is already linked against UCRT (i.e. when building in the UCRT64 environment), the linked-in `strftime()` is the ucrtbase.dll version, making the dynamic loading needless churn: It's calling the very same code. Simply guard both the declaration and implementation so that the unnecessary work-around is skipped in UCRT builds. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Currently, Git for Windows is built off of the MINGW64 tool chain. But this will have to change because [the MSYS2 project deprecated this tool chain in favor of UCRT64](https://www.msys2.org/news/#2026-03-15-deprecating-the-mingw64-environment). Of course, that's only possible because they dropped support for Windows 8.1, which Git for Windows will probably have to do relatively soon. The best time to do that is probably [the Git 3.0 inflection point](git-for-windows#6018) when we already promised to drop support for older Windows versions. To prepare for such a huge change, I investigated what needs to be changed in Git for Windows' source code. And the good news is there's actually not very much. This here patch seems to be the only change that's necessary, and not even _strictly_ necessary: the `mingw_strftime()` wrapper would still do the right thing. It would just uselessly load the same function that's already loaded, dynamically, again. - The `strerror()` override [is guarded by an `#ifndef _UCRT`](https://github.com/git-for-windows/git/blob/v2.53.0.windows.2/compat/mingw-posix.h#L294-L296), - `PRIuMAX` resolves to standard `"llu"` [via `<inttypes.h>`](https://github.com/git-for-windows/git/blob/v2.53.0.windows.2/compat/mingw-posix.h#L449-L454) (note that `__MINGW64_VERSION_MAJOR` is defined both in MINGW64 and UCRT64, by virtue of using the `mingw-w64-headers`), - [`__USE_MINGW_ANSI_STDIO=0`](https://github.com/git-for-windows/git/blob/v2.53.0.windows.2/config.mak.uname#L751C19-L751C33) is irrelevant because [`_UCRT` short-circuits it](https://github.com/git-for-windows/git-sdk-64/blob/08933e673c79b5db48419917a2b02746b390afc4/mingw64/include/inttypes.h#L33), and - `SNPRINTF_RETURNS_BOGUS` hasn't been set for Git for Windows' builds since ec47a33, i.e. for a _really_ long time.

Currently, Git for Windows is built off of the MINGW64 tool chain. But this will have to change because [the MSYS2 project deprecated this tool chain in favor of UCRT64](https://www.msys2.org/news/#2026-03-15-deprecating-the-mingw64-environment). Of course, that's only possible because they dropped support for Windows 8.1, which Git for Windows will probably have to do relatively soon. The best time to do that is probably [the Git 3.0 inflection point](#6018) when we already promised to drop support for older Windows versions. To prepare for such a huge change, I investigated what needs to be changed in Git for Windows' source code. And the good news is there's actually not very much. This here patch seems to be the only change that's necessary, and not even _strictly_ necessary: the `mingw_strftime()` wrapper would still do the right thing. It would just uselessly load the same function that's already loaded, dynamically, again. - The `strerror()` override [is guarded by an `#ifndef _UCRT`](https://github.com/git-for-windows/git/blob/v2.53.0.windows.2/compat/mingw-posix.h#L294-L296), - `PRIuMAX` resolves to standard `"llu"` [via `<inttypes.h>`](https://github.com/git-for-windows/git/blob/v2.53.0.windows.2/compat/mingw-posix.h#L449-L454) (note that `__MINGW64_VERSION_MAJOR` is defined both in MINGW64 and UCRT64, by virtue of using the `mingw-w64-headers`), - [`__USE_MINGW_ANSI_STDIO=0`](https://github.com/git-for-windows/git/blob/v2.53.0.windows.2/config.mak.uname#L751C19-L751C33) is irrelevant because [`_UCRT` short-circuits it](https://github.com/git-for-windows/git-sdk-64/blob/08933e673c79b5db48419917a2b02746b390afc4/mingw64/include/inttypes.h#L33), and - `SNPRINTF_RETURNS_BOGUS` hasn't been set for Git for Windows' builds since ec47a33, i.e. for a _really_ long time.